No, he's not based on IO. He is, in fact, based on the Medic from TF2.

Backstory wise, he's evil as hell. Keeps trying to kill people in various ways but all of his inventions somehow end up helping instead of causing harm. He joins the league so he can at least help people kill other people, since he's clearly inept at killing them himself.

Abilities

Power Link

Right-clicking on an allied champion links Franz to it if they are within his attack range, enabling some of his other abilities. While linked, Franz's basic attack is disabled and he gains 10% movement speed. The tether breaks if Franz is more than 525 units from his target.

Malfunctioning Death Ray

COST: 10 / 15 / 20 / 25 / 30 mana per second

COOLDOWN: 10 / 9 / 8 / 7 / 6

Toggle: Franz heals his linked ally every second, while reducing the damage it takes. If Franz has no linked ally, he heals himself instead. Enemies caught in the beam take damage equal to double the heal, every second.

Heal per Second: 10 / 15 / 20 / 25 / 30 (+ 10% AP)

Damage Reduction: 12 / 14 / 16 / 18 / 20%

Ally Removal Device

RANGE: 875

COST: 70 mana

COOLDOWN: 16

Active: Creates a strange device which explodes over a target area, granting all allied units hit movement speed and stealth. If activated while linked with an ally, Franz and his ally gain the bonus regardless of if the device hits them.

Movement Speed: 10 / 12 / 14 / 16 / 18

Duration: 2 / 2.5 / 3 / 3.5 / 4 (+ 0.5 seconds per 100 ap)

Rage Inducer

COST: 70 mana

COOLDOWN: 18 / 16 / 14 / 12 / 10

Active: Grants linked ally bonus attack damage and ability power for a duration. Enemies caught in the beam during this time are slowed by 25%. Cannot be cast without a linked ally.